Manufacture of 1-nitro-anthraquin-one-6-carboxylic acid



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:Th invention relates tiomof tediousand impractical fon useon-a commercial scale. It was devised by -Eckert,,(Monats .;,35, 289-296;;1314) According to this known procsz zemet r rnth aqu ncn is brominatedi to produce omega-di-bromo-2-methyl-anthraquinone whichis in turn hydrolyzedto anthraquinone-Z-aldehyde. Thereafter this product (the aldehyde) is nitrated, producing l-nitro-anthraquinone-G-aldehyde which compound is subsequently oxidized to l-nitro-anthraquinone-ficarboxylic acid.

This invention has for an object the preparation of l-nitro-anthrfaquinone-G-carboxylic acid by a novel process, its preparation by a process which is commercially practical and its preparation by a greatly simplified procedure. Other objects are the nitration of anthraquinone-2-carboxylic acid. and the development of a process which makes available for the synthetic dye industrya valuable organic chemical. A still fur-, ther object is the nitration of 2'-anthraquinonecarboxylic acid with nitric acid in the presence of sulfuric acid. A general advance in the art and other objects which will appear hereinafter, are also contemplated.

These objects are accomplished by treating anthraquinone-2-carboxylic acid with nitric acid.

The invention will be further understood from a consideration of the following detailed description and specific examples in which the parts are given by weight. I i 1 Ewample I Ten (10) parts of anthraquinone-2-carboxylic acid were dissolved in one hundred (100) parts of 95% sulfuric acid and cooled to 0 C.-5 C. Twelve (12) parts of a mixture consisting of 32% nitric acid (HNOs) and 68% sulfuric acid (H2804) were added tothe sulfuric acid solution. After about one-half hourallowed to rise to 20 C.- C. and held within that range for 1-2 hours. The reaction mass was then drowned in water and filtered. The residue, after drying was added to, 12-15 times its weight of boiling glacial acetic acid. After boiling the resultant for one-half to one hour, it was cooled to about C.1Q0

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V wer i p to ithe preparation fof, carbonqcompounds and more particularly-to the;

preparation 1 of, ,1wnitroranthr quinoncefi carb xr ylic. acid. 1 It. especially contemplates the, nitra c en cranthr qu n erfiecarb r c, a id." i. oner perior. results.

the temperature was C. and filtered.

Ten (10) parts ti dry 1 anthraduinone fifcar oziy i a d. were. slowly ad ed a o n n e arboxylic aci'dfwhich separated from the oneresultant solution was filteredi'off on a stone filter. After allowing the filtrate to stand for one to two days, a second crop of l-nitro-anthraquinone-6-carboxylic acid was obtained by similar filtration. I

The invention, of course, is not limited to the specific details set out in the above examples.

A widevariety of conditions. may be employed as will be clear to those skilled in the art. The particular conditions set out in the examples are v those, which have been found to give very desirable results. It is not necessary that the anthraquinone-2-carboxylic acid be dissolved in sulfuric acid before the treatment with nitric acid; Ifdesired the nitration may be accomplished by the use of nitric acid alone as indicated inExam ple II: v f

The proportion of anthraquinone-2-carboxylic acid and nitrating medium, may be varied to suit the will: of-the person carrying out the nitration process. A greater proportion of nitrating medium than that disclosed in the examples, while usable has not been found to give generally su- Lesser proportions of nitrating, medium than that mentioned in the examples,

tend to slow down the reaction. When the Nitrationscarried out attemperatures greater than thoseutilized in the specific examples tend to give a less desirable productalthough such high temperatures can be used if desired; Lower temperatures than those of the specific examples tend to slow down the reaction. In addition entails mechanicaldifficulties and is a source of added'expense. I

to this disadvantage the lower temperatures are not desirable for-the reason that refrigeration The time of. nitration is readily'determined empirically. A satisfactory method of testing comprises analyzing a test portion of the product' fornitrogen. Apparently no advantage is gained by carrying out the treatment with the nitrating medium after the desired nitration has taken places The proportion of acetic acid and temperature. utilized for the recrystallization of the l-nitro- 10 anthraquinone -G-carboxylic acid may be' reguilated to suit the rying out that step of the process.

This invention has the advantage thata tam; intermediate is preable organic chemical and pared by a very simple commercially practical process.

As many apparently widely'different embodiments of this invention may be made without departing from the spirit and scope thereof, it

' is to be understood that we do not limit ourselves to the specific embodiments thereof except as defined in the appended claims. ,=Wec1aim:. i

1. The process which comprises mixing about 10 parts of anthraqhinone-Z-carboxylic acid with about 100 parts of concentrated sulfuric acid, adjusting the temperature to about C C., adding about 12 'parts' of a mixture consisting of about 32 parts o fnitric acid and about 68 parts of sulphuric acid; after about one-half hour adjusting the temperature to about 20 C.'60 0.,

convenience of the personicar-gj V justing the temperature to about 20 ing the residueto about 12-15 times maintaining this temperature for about I-2 e hours, drowning the reaction mass in water and nitrated anthraquinone-carboxfiltering off the ylic acid.

e v2, The process which comprises mixingabout 'parts of anthraquinone z-carboxylic acid with about 100 parts of concentrated sulfuric acid, adjusting the temperature toabout 0 (IL-5 C., addglacial acetic acid, boiling the mixture for about one-half to one hour, adjusting the temperature to about 90 (L-100 C. and filtering. v

p 3. The reaction-mass y about- 1f) parts of anthraquinone-z-carbdxylic acid with about 100 parts of concentrated sulfuric acid, adjusting-the temperature to about 0 'C.-'

5 0., 7 adding about 12' parts of a mixture consisting ofabout 32 parts of nitric acid and about 68 parts of sulfuric acid, after about" one-half hour adjusting the temperature to about C.- C. and maintaining this temperature 'for about 1-2 hours. r 7 EARL EDS'ON BEARD.

NQRBERT umx.

obtainable by 

